Open minimal pane mode programatically

[ghost]

When I set NavigationPane's displayMode to PaneDisplayMode.minimal, NavigationView is hidden.
Without appBar, I tried to find another way to call its menu event, but I couldn't find it.
How will I make it show again?
NavigationView seems to rely on a bool property called'_ minimalPaneOpen' to control whether it is shown or hidden (in PaneDisplayMode.minimal mode), but when I try to set it through key, I can't find an external way to set it.